SWP_MIGRATION_NUM   67 include/linux/swap.h #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
SWP_MIGRATION_NUM   68 include/linux/swap.h #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
SWP_MIGRATION_NUM   96 include/linux/swap.h 	SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)